Structural foamed panel and method of making the same

ABSTRACT

A panel or multi-panel structure in which each of the panels includes a pair of spaced substantially planar sheets connected with one another by connection members and a foam core.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a structural panel for use by numerousmarkets including the Department of Defense. These lightweightcomponents are used as structural members on items such as vehicles andradar structures. The combination of lightweight (metallic, plastic,composite) member and a lightweight foam application that is applied inthe open cavity produces favorable results for these customers. Thesepanels are typically custom designed to the customer'sapplication/shape, monolithic/high velocity machined, fastened togethervia new technology and then foamed. There is also a benefit with thethermal/acoustic characteristics that this product provides forinsulating certain components. The invention also relates to thenumerous combined methods of manufacturing and fastening the components.

2. Description of the Prior Art

The need for force mobility in the Armed Services (along with fuelcosts) is driving development of a new generation of lightweightmaterial solutions. Many earlier systems and components were built veryheavy with thick metallic cross sections for safety and performancebenefits. The introduction of new high velocity machining technology hasnow given manufacturers the option for thinner, lighter components ifthey can meet the structural/stress requirements. Many of these earliercomponents were also fastened with heavy bolts and rivet type hardware,further increasing the weight of a vehicle or system. Composites havebeen a costly lightweight alternative that have numerous manufacturingissues from expensive/complex tooling needs to distortion, disposal andrepair of base composite.

SUMMARY OF THE INVENTION

The present invention relates to a structural component or panel andmulti-panel structure that utilizes various new manufacturing methods toproduce a strong, lightweight composite alternative. This invention islighter than traditional aluminum structures and less expensive thancurrent composite components.

The present invention can be comprised of a single metallic component orpanel or multiples depending on the design needed. These components orpanels are machined from blocks of material utilizing the latestmonolithic grid and thin walled processes in the marketplace. Surfacetreatments are then specified based on the fastening and adherencerequirements. The panels can then be foamed before fastening or after.Many of these panels will utilize quick connection systems such as theconnection system of pending U.S. patent application Ser. No. 11/094,331filed Mar. 30, 2005 (hereinafter “Pending Connection Mechanism”), theentirety of the substance of which is incorporated herein by reference.Many may also utilize friction stir welding or epoxy processes to jointhe multiple pieces. Once the core is foamed, additional precisionmachining can be accomplished to add critical features or to furtherthin or machine walls and surfaces. The form core acts as a support toallow thinning of certain features, further reducing weight. Thesecomponents can also contain cooling components (cold plates) and otherstructural features for mounting, coolant passage, or componentclearance depending on design needs. Contoured or multi-axis surfacesand features will also be attainable with this invention.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a pair of structural panels made inaccordance with the present invention. The component at the bottomincludes a pair of aluminum plates filled with foam and a pair ofconnection rails at the top. The upper component includes a pair ofspaced aluminum plates with foam therebetween and a base designed forconnection to the connection rails. The rails form a connectionmechanism similar to that of the Pending Connection Mechanism.

FIG. 2 is a top view showing a portion of a structural panel of FIG. 1in accordance with the present invention connected with a base plate.The structural panel includes a web with radii mating with the surfaceplates. The area between the surface plates is filled with a foam.

FIG. 3 is comprised of FIGS. 3 a and 3 b. These figures are perspectiveviews showing a pair of panel structures similar to those shown in FIGS.1 and 2.

FIG. 4 is comprised of FIGS. 4 a and 4 b. These figures are perspectiveviews showing the panel structures of FIGS. 1-3 in which the verticallypositioned panel is connected with the base panel.

FIG. 5 is a further embodiment of a structural panel in accordance withthe present invention, shown in cross-section. The top surface panel isintegrally connected with a pair of struts and an end wall, while thebottom surface panel is connected with the struts via the PendingConnection Mechanism. The core is filled with foam.

FIG. 6 is a view, partially in section, of a base panel and a pair ofintegral, laterally spaced struts and an integral end wall. The topsurface panel is connected with the struts via a pair of threadedmembers and is connected to the end wall by the above-described PendingConnection Mechanism. The interior cores between the plates and thestruts are filled with a foam material.

FIG. 7 is a further embodiment of a structural panel in accordance withthe present invention in which the bottom aluminum surface panel isintegrally formed with an end wall and a partial front wall. The topsurface panel is connected with the end wall and the partial front wallvia the above-described Pending Connection Mechanism. The area betweenthe panels is filled with a foam.

FIG. 8 is a view, partially in section, of a further embodiment of thestructural panel of the present invention. The base surface panel isintegrally formed with a pair of struts and an end wall and the topsurface panel is connected with the struts and the end wall via thePending Connection Mechanism. The interior cores are filled with foammaterial.

FIG. 9 is comprised of FIG. 9 a and FIG. 9 b. FIG. 9 b is a sectionalview showing the structure of a typical structural panel in accordancewith the present invention with the base surface sheet integrally formedwith a vertically extending strut and with the top surface sheet havinga pair of prongs or connection members to connect with the distal end ofthe strut. The connection system between the top surface sheet and thestrut is in accordance with the above-described Pending ConnectionMechanism. The cores within the panels are filled with a foam. FIG. 9 bshows the connection members before connection.

FIG. 10 is a view showing relative dimensions in one embodiment of astructural foam panel between the aluminum and the foam.

FIG. 11 is a sectional view of an embodiment of the present inventionsimilar to the embodiment of FIGS. 1-4. This embodiment comprises alightweight foam or monolithic configuration.

FIG. 12 is a perspective view of an embodiment of the foam corestructure shown in FIGS. 1-4.

FIG. 13 is an enlarged view of the connection between an edge of avertical panel structure and the outer surface of a base panel structureof the embodiment of FIGS. 1-4. This connection utilizes the PendingConnection Mechanism in which a pair of connection prongs or connectionmembers are integrally formed with the outer surface panel of the basefor connection with prongs of the vertical panel.

In the above embodiments, all panel components are constructed ofaluminum or other lightweight metals such as titanium and the cores arefilled with a curable foam.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is directed to a structural component or panel inwhich a pair of sheets are connected to one another via one of a varietyof connection mechanisms such as those disclosed in pending U.S. patentapplication Ser. No. 11/094,331 filed Mar. 30, 2005, the entirety of thesubstance of which is incorporated herein by reference. Such structuralcomponents or panels are then filled with a foam core to provide alightweight, high strength structural component or panel. The inventionis also directed to a method of making such a panel and to a multi-panelstructure in which two or more panels are connected together.

In the preferred embodiment, portions of a panel or multiple panels areconnected to one another utilizing the connection mechanism techniquesdescribed and disclosed in the above-mentioned pending U.S. patentapplication Ser. No. 11/099,331. The connection mechanism disclosedtherein generally includes a pair of female connecting members orsurfaces and a corresponding pair of male connecting members or surfaceswhich are capable of being mechanically interlocked with one another asa result of grooves or recesses on one of the members or surfaces andcorresponding connection ribs on the other.

FIGS. 9 and 13 show examples of such connection mechanisms. FIGS. 9 aand 9 b show the connection of a first or lower substantially planarsheet 10 with a second or upper spaced substantially planar sheet 11 toform the panel 12. As shown, the sheet 10 includes one or more outwardlyextending struts 14 integrally formed with the sheet 10. The outer end15 comprises an enlarged head with connection surfaces facing away fromone another. The connection surfaces include shoulder portions 16 whichtransition to the narrower strut portion 14. The opposite, spaced sheet11 includes a female portion comprised of the pair of connection members18. These members 18 include inwardly facing connection surfaces whichinclude the enlarged portion or rib 19. When the sheet 11 is positionedrelative to the sheet 10 so that the members 18 are aligned with theportion 15 as shown in FIG. 9 b and pressed together, the head portion15 is inserted between the members 18 and is retained in that positionby engagement between the ribs 19 and the shoulders 16. If desired, thismechanical connection can then be further joined and retained by asecondary connection mechanism such as epoxy, friction stir welding orother means. If epoxy is used, one or the other or both of the inside ofthe members 18 or the outside of the members 15 and 16 is provided withan epoxy adhesive prior to snapping the two parts together. If asecondary connection mechanism such as friction stir welding isutilized, friction stir welding may be applied along the area indicatedby the reference character 20 in FIG. 11 a. Although the panel formed bythe sheets 10 and 11 shows only a single strut 14, it is contemplatedthat a typical panel will include a plurality of struts 14 positionednear the ends of the panel and laterally spaced throughout the panel. Itis intended that the panel will also include edges between and aroundthe periphery of the sheets.

FIG. 13 shows a preferred mechanism for connecting an edge of one panel21 to the surface of a second panel 22. As shown, the panel 22 to whichthe panel 21 is to be connected includes a first substantially planarsheet 24 and a second substantially planar sheet 25. The outer surfaceof the sheet 25 includes a pair of spaced connection members 26extending outwardly from the outer surface of the sheet 25. Each ofthese members 26 includes a pair of connection surfaces having a widenedrib portion 28 facing the other member 26. The edge of the panel 21 tobe connected to the panel 22 includes a male member comprised of a pairof spaced connection surfaces 29 facing away from one another. Thesurfaces 29 include a pair of grooves or recessed areas 30. When thepanel 21 is positioned relative to the panel 22 so that the edge 23 isaligned between the members 26, the surfaces 29 slide between themembers 26 and the shoulders or enlarged areas 28 snap into the grooves30, thereby retaining the panel 21 relative to the panel 22. Ifadditional connection means are needed or desired, epoxy, friction stirwelding or other connection techniques may be utilized. If friction stirwelding is to be utilized, it may be applied between one or both of themembers 26 and a corresponding portion of the surface 29 or groove 30 asshown by the reference character 31 in FIG. 13.

Having described the details of the connection mechanisms and techniquesbetween a pair of sheets to form panels and between a pair of panels toform a multi-panel structure, specific structural components and panelscan be described with respect to the remaining figures as follows.

In FIG. 1, an edge 32 of the foamed panel 34 is connected to the topouter surface 35 of the foamed panel 36. As shown, the outer surface 35of the panel 36 is provided with a pair of outwardly extendingconnection members 38,38 to mate with corresponding surfaces 39,39 ofthe panel edge 32. In this embodiment, the connection members 38,38 andthe connection surfaces 39,39 are similar in detail to those shown inFIG. 15.

FIG. 2 shows a foamed panel 40 with a bottom edge connected to a baseplate 41. In this embodiment, the base plate 41 may be the outer surfaceof a second foamed panel or a single sheet of material. As shown in thisfigure, the panel 40 is provided with a web 42 to provide additionalstrength and rigidity to the panel 40. The edge of the panel 40 and thesurface of the base plate 41 which are connected to one another areprovided with a connection mechanism similar to that shown in FIG. 15.

FIG. 3 comprised of FIGS. 3 a and 3 b shows a pair of interconnectedfoamed panel structures similar to those of FIGS. 1 and 2. In FIG. 3 a,an edge of the panel 44 is connected to an outer surface of the panel 45utilizing a connection mechanism similar to that shown in FIG. 15. FIG.3 b shows an edge of the panel 46 connected with an outer surface of thepanel 48 utilizing a connection mechanism of FIG. 15. In FIG. 3 b, thepanel 46 is provide with one or more reinforcing struts or webs 49integrally formed with and positioned between the sheets of the panel46.

FIG. 4 comprised of FIGS. 4 a and 4 b shows further examples ofstructural components formed by connecting an edge of one foamed panelto the outer surface of a second foamed panel. In FIG. 4 a, an edge ofthe panel 50 is connected to an outer surface of the panel 51, while inFIG. 4 b, an edge of the panel 52 is connected to an outer surface ofthe panel 54. In both embodiments, the connection mechanism is similarto that shown in FIG. 15.

FIG. 5 is a foamed panel comprised of spaced first and second sheets 55and 56, respectively. The sheet 56 includes a pair of downwardlyextending and integrally formed struts 58, while the bottom sheet 55includes two pair of spaced connection members 59 which mate with theouter ends of the struts 58. The details of the connection portions andsurfaces of the struts 58 and the members 59 are similar to those shownin FIGS. 11 a and 11 b for connecting sheets to form a panel. Followingconnection, the interior of the panel is foamed.

FIG. 6 shows a panel 64 comprised of a lower sheet 69, a spaced uppersheet 70 and a plurality of integral studs or struts extending upwardlyfrom the sheet 69. The sheet 70 is connected with the studs via threadedconnection members in the threaded openings 72. The side edges of thepanel 64 are provided with a connection mechanism 63 similar to thatshown in FIGS. 11 or 15.

FIG. 8 shows a pair of substantially planar sheets 74 and 75 connectedtogether to form the panel 76. The panel structure of FIG. 10 is similarto that of FIG. 5 except that the panel sheets are reversed. The panelof FIG. 8 utilizes the connection mechanism shown in FIG. 11. Theinterior of the panel 76 and each of its interior chambers is foamed.

FIG. 10 shows the dimensional relationship between the sheets 78 and 79and the foam core 80 of a typical panel 77 in accordance with thepreferred embodiment. In the preferred embodiment, the foam whichcomprises the foam core of the various panel embodiments is a curablefoam known in the art such as polyurethane, polyethylene andpolystyrene, among others. Such foam is preferably introduced into thecore of the panels through an opening in one of the panel sheets afterthe sheets have been connected to form the panel. In many cases, theport or opening for introducing the foam into the panel cores can bepositioned between the connection members 26,26 such as is shown in FIG.13.

FIG. 11 is a view, similar to claim 1, with panel 34 connected with thepanel 36.

FIG. 12 is an isometric view of the structural panel shown in FIG. 13.

Although the preferred embodiment has been quite specific, it iscontemplated that various modifications could be made without deviatingfrom the spirit of the present invention. Accordingly, it is intendedthat the scope of the present invention be dictated by the appendedclaims rather than by the description of the preferred embodiment.

1. A structural panel comprising: a first substantially planar sheethaving an inner surface and an outer surface; a second substantiallyplanar sheet having an inner surface and an outer surface, said firstand second sheets spaced from one another with their respective innersurfaces facing one another; the inner surface of one of said first andsecond sheets including a first connection member extending therefromand the inner surface of the other of first and second sheets includinga second connection member extending therefrom, said first and secondconnection members being connectable to one another to maintain saidfirst and second sheets in spaced relationship; and a foam core betweensaid paced first and second sheets.
 2. The panel of claim 1 wherein oneof said first and second connection members includes a plurality ofstruts extending between said first and second sheets.
 3. The panel ofclaim 2 wherein one end of said struts is integrally formed with one ofsaid first and second sheets.
 4. The panel of claim 3 wherein the otherend of said struts includes a head having a pair of connection surfaces.5. The panel of claim 4 wherein the other of said first and secondconnection members is integrally formed with the other of said first andsecond sheets.
 6. The panel of claim 5 wherein one of said first andsecond connection members includes a pair of connection surfaces facingtoward one another and the other of said first and second connectionmembers includes a pair of connection surfaces facing away from oneanother.
 7. The panel of claim 6 including an edge extending betweensaid sheets around the periphery of said sheets.
 8. The panel of claim 1including an edge extending between said sheets around the periphery ofsaid sheets.
 9. The panel of claim 1 including a plurality of laterallyspaced webs between said sheets.
 10. A method of making a structuralpanel comprising: providing first and second substantially planarsheets; connecting said first and second sheets to one another in spacedrelationship; and injecting a foam material between said first andsecond spaced sheets.
 11. The method of claim 10 including forming anedge between said sheets and around the periphery of said sheets.
 12. Amulti-panel structure comprising: a first foamed panel having a pair ofspaced, substantially planar sheets, a plurality of connection membersbetween said first and second sheets to connect said sheets to oneanother and maintain said sheets in a spaced relationship and a foamcore between said sheets; a second foamed panel having a pair of spaced,substantially planar sheets, a plurality of connection members betweensaid first and second sheets to connect said sheets to one another andmaintain said sheets in a spaced relationship and a foam core betweensaid sheets; one of said first and second panels including an outersurface having a pair of spaced first connection members extendingoutwardly from said outer surface; the other of said first and secondpanels including a panel edge, said edge including spaced secondconnection members, said first and second connection members connectableto one another to connect the edge of said other panel to the outersurface of said one panel.
 13. The structure of claim 12 wherein one ofsaid first and second connection members includes a pair of connectionsurfaces facing toward one another and the other of said first andsecond connection members includes a pair of connection surfaces facingaway from one another.
 14. The structure of claim 13 wherein said firstconnection members includes a pair of connection surfaces facing towardone another and said second connection members includes a pair ofconnection surfaces facing away from one another.
 15. The structure ofclaim 14 wherein one of pair of connection surfaces includes aconnection rib and the other or said pair of connection surfacesincludes a connection recess.
 16. The structure of claim 15 wherein saidconnection ribs and said connection recesses are connectable to oneanother.